Snagging grinder



March 29, 1955 c. SODERLUND SNAGGING GRINDER 5 Sheets-Sheet 2 Filed Oct.2, 1952 A m w L S L MW Ill: a

INVENTOR. CARL SUDER'L u vu BY M 'wom.

March 29, 1955 c. SODERLUND 2,

SNAGGING GRINDER Filed Oct. 2, 1952 3 Sheets-Sheet 3 orr 0/1. PUM

Moral? WHEEL MOTO 1m EN TOR. 4 CARI. SUDERLUND United States PatentSNAGGING GRINDER Carl Soderlund, Worcester, Mass., assignor to NortonCompany, Worcester, Mass, a corporation of Massachusetts ApplicationOctober 2, 1952, Serial No. 312,715

4 Claims. (Cl. 5147) The invention relates to grinding machines, andmore particularly to a snagging grinder for surfaclng steel billets andthe like.

One object of the invention is to provide a simple and thoroughlypractical snagging grinder. Another object is to provide a snagginggrinder which is arranged so that it may be operated and controlled witha minimum of manual exertion. Another object is to provide a snagginggrinder in which the grinding wheel may be readily traversedlongitudinally, also transversely, and may be rocked laterally through acomparatively short arcuate path for grinding small areas of the workpiece. A further object of the invention is to provide a snagginggrinder in which the grinding wheel may be traversed longitudinally toposition the wheel relative to the work piece being ground and may beoscillated or reciprocated through a shorter stroke to grind a portionof the work piece. A further object is to provide a yieldable pressurecontrol whereby the grinding wheel may be mamtained in grindingengagement at the desired pressure during an oscillating orreciprocating movement of the grinding wheel. Other objects will be inpart obvious or in part pointed out hereinafter.

In the accompanying drawings in which is shown one of the variouspossible embodiments of the mechanical features of this invention:

Fig. 1 is a side elevation of the snagging grinder;

Fig. 2 is a horizontal sectional view, taken approximately on the line22 of Fig. 1 showing the snagging grinder in elevation;

Fig. 3 is a vertical sectional view, on an enlarged scale, takenapproximately on the line 33 of Fig. 1;

Fig. 4 is a fragmentary sectional view, on an enlarged scale, takenapproximately on the line 44 of Fig. 1;

Fig. 5 is a fragmentary horizontal sectional view, on

an enlarged scale, taken approximately on the line 5--5 of Fig. 1;

Fig. 6 is a vertical sectional view, on an enlarged scale, takenapproximately on the line 6-6 of Fig. 7, through one of the controlvalves; and

Fig. 7 is a combined electric and hydraulic diagram of the actuatingmechanisms and the controls of the machine.

A snagging grinder has been illustrated in the drawings comprising apair of parallel overhead I-beams 10 and 11 which serve as a support fora longitudinally movable carriage 12. The carriage 12 is provided with aplurality of pairs of rollers 13, 14, 15 and 16 which ride upon surfacesof the I-beams 10 and 11 and form a roller support for the carriage 12.

A traversing mechanism is provided for moving the carriage 12longitudinally comprising a shaft 17 rotatably supported on the carriage12. The shaft 17 is provided with a pair of driving wheels 18 and 19(Fig. 2) which drivingly engage surfaces on the I-beams 10 and 11. Asecond drive shaft 20 is rotatably supported on the carriage 12 spacedfrom the shaft 17. The drive shaft 20 is provided with a pair of drivingwheels 21 and 22 which similarly engage surfaces on the I-beams 10 and11. A fluid motor 23 supported on the carriage 12 is connected by a linkchain 24 with a rotatable shaft 25. The shaft 25 is connected by a linkchain 26 with the shaft 17. The shaft 17 is provided with a sprocket 27which is connected by a link chain 28 with a sprocket 29 on the shaft20. It will be readily apparent from the foregoing disclosure thatrotary motion of the fluid motor 23 will be imparted through the linkchain driving mechanism above de- 2,704,913 Patented Mar. 29, 1955scribed synchronously to rotate the shafts 17 and 20 thereby rotatingthe driving wheels 18-19 and 21-22 to traverse the carriage 12longitudinally along the I-beams 10 and 11.

The carriage 12 consists of a pair of plates 30 and 31 (Fig. 2). The endportions of the plates 30 and 31 are clamped around a pair of spacedtransversely extending tubular members 35 and 36. The plate 30 serves asa support for the traversing mechanism previously described and also forsupporting wheels 13 and 14 and one end of the drive shafts 17 and 20.Similarly the plate 31 serves as a support for the wheels 15 and 16 andalso for the other ends of the drive shafts 17 and 20. The end portionsof plates 30 and 31 surround a portion of the tubular rods 35 and 36 andare provided with clamping plates to support the rods 35 and 36 on thecarriage 12.

A cross plate 37 is provided with enlarged end portions 38 and 39 whichsurround the tubular rods 35 and 36 respectively and are clampedthereto. The plate 37 serves as a support for a pair of spacedvertically arranged tubular members 40 and 41, the lower ends of whichsupport an operators control platform 42 which travels longitudinallywith the carriage 12. The control platform 42 is provided with a controlapparatus to be hereinafter described whereby the operating mechanismsof the machine may be readily controlled during longitudinal movement ofthe carriage 12.

The tubular rod 36 serves as a support for a plate 45. The right-handend of the platen 45 has an enlarged portion 46 surrounding the tubularrod 36. The platen 45 is provided with two spaced depending bosses 47and 48 having bearings (not shown) for supporting a rock shaft 49. Therock shaft 49 supports a vertically arranged depending hollow column 50.The column 50 is provided with an enlarged upper portion 51 which isfixedly supported on the rock shaft 49. The lower end of the column 51is provided with a bracket 52 which supports a rock shaft 53. The rockshaft 53 in turn supports a bracket 54 having an enlarged lower portion55 which surrounds a cylindrical portion formed on a swing frame grinder56. The swing frame grinder 56 may be any one of the well knowncommercial units having a wheel spindle 57 mounted at one end thereof.The wheel spindle 57 being arranged to support rotatable grinding wheel58. The grinding Wheel 58 is partially surrounded by a wheel guard 59.The other end of the swing frame grinder is provided with a rock shaft60 which supports a motor platen 61 having an electric motor 62 fixedlymounted thereon. The motor 62 is provided with a multiple V-groovepulley 63 which is connected by V-belts 64 and 65 which are connected toV-grooves formed in the periphery of a pair of wheel flanges 66 and 67supporting the grinding wheel 58. An adjusting screw mechanism 68 isprovided to facilitate adjusting the position of the motor platen 61 soas to tension the V-belts 64 and 65 as desired.

A work piece such as a billet 70 to be ground is mounted on a stationarywork support 71. The vertical column 50 is arranged to swing with therock shaft 49 to cause a transverse movement of the swing frame grinder56. The swing frame grinder 56 is arranged to swing about the rock shaft53 so as to maintain the grinding Wheel 58 in operative engagement withthe work piece 70 being ground.

A hydraulically operated control mechanism is provided for rocking theswing frame grinder 56 in a plane normal to its longitudinal axis, torock the swing frame grinder about the axis of the rock shaft 53, torock the column 50 about the axis of the rock shaft 49, and to rock theplaten 45 about the axis of the tubular rod 36. This mechanism maycomprise a hydraulic cylinder having a slidably mounted piston 76connected to one end of a piston rod 77. The cylinder 75 is pivotallyconnected by a stud 78 with a bracket 79 depending from the platen 45.The right hand end of the piston rod 77 (Fig. l) is connected by a studS6 with an arm 81 which is fixedly mounted on the rock shaft 49. It willbe readily apparent from the foregoing disclosure that when fluid underpressure is passed through a pipe 82 into a cylinder chamber 83, thepiston 76 will be caused to move toward the right (Fig. 7) to impart acounterclockwise swinging movement to the vertical column 50 and theparts supported thereby. During this movement fluid within a cylinderchamber 84 is exhausted through a pipe 85. It will be readily apparentthat when the flow of fluid is reversed and fluid under pressure passesthrough the pipe 85 into the cylinder chamber 84 a clockwise swingingmovement will be imparted into the column 50.

A hydraulic cylinder 90 contains a slidably mounted piston 91 which isconnected to the right hand end of a piston rod 92. The cylinder 90 ispivotally connected by means of a stud 93 with a bracket 94 which isfixedly mounted on the column 50. The lower left hand end of the pistonrod 92 is provided with a transversely extending stud 89 which isconnected by a pair of spaced tension springs 94 and 95 with a stud 96carried by a slidably mounted sleeve 97 (Fig. 4). A sleeve 97a surroundsthe piston rod 92 and is interposed between the sleeve 97 and the pin 89to limit the sliding movement of the sleeve 97 relative to the pistonrod 92. The sliding sleeve together with the springs 9495 serve toprovide a yielding connection between the piston rod 92 and the arms98-99. The slidably mounted sleeve 97 is slidably supported on thepiston rod 92. The sleeve 92 is pivotally connected to a pair of spacedarms 98 and 99, the lower ends of which are fixedly mounted on the rockshaft 53. It will be readily apparent that when the fluid under pressureis passed through a. pipe 100 into a cylinder chamber 101, the piston 91will move toward the left (Fig. 7) so as to rock the arms 98 and 99 in acounterclockwise direction (Fig. 1) about the axis of the rock shaft 53to impart a counter-clockwise swinging movement to the swing framegrinder 56. During this movement fluid within a cylinder chamber 102 mayexhaust through a pipe 103. Similarly if the fluid under pressure isreversed so that it flows through the pipe 103, a clockwise swingingmovement will be imparted to the swing frame grinder 56 about the axisof the rock shaft 53. It will be readily apparent from the foregoingdisclosure that the tension springs 94 and 95 serve to provide ayielding connection so that the grinding wheel 58 may be yieldinglymaintained in operative engage ment with the work piece 70 being ground.

A hydraulic cylinder 105 contains a slidably mounted piston 106 which isconnected to one end of a piston rod 107. The cylinder 105 is pivotallyconnected by a stud 108 carried by the bracket 54 which supports theswing frame grinder unit 56. The right hand end of the piston rod 107 isconnected by a stud 109 with an arm 110 which is fixedly mounted on theswing frame grinder unit 56. When fluid under pressure is passed througha pipe 111 into a cylinder chamber 112, the piston 106 will be movedtoward the left (Fig. 7) to rock the arm 110 in a clockwise direction.During this movement fluid within a cylinder chamber 113 may exhaustthrough a pipe 114. Similarly if the fluid under pressure is reversedand fluid under pressure passes through the pipe 114, the arm 110together with the swing frame grinder unit 56 will be rocked in acounter-clockwise direction about the lonigtudinal axis of the swingframe grinder unit 56. This mechanism serves to facilitate swinging thegrinding wheel so that grinding may be done by either (Susie cornerportion or the other of the grinding wheel A hydraulic cylinder 115contains a slidably mounted piston 116 which is connected to the upperend of a piston rod 117. The cylinder 115 is pivotally connected by astud 118 with a bracket 119 which is fixedly mounted on the tubular rod35 and the carriage 12. The lower end of the piston rod 117 is connectedby a stud 120 with a yoked member 121 which is rotatably supported onthe rock shaft 49. When fluid under pressure is passed through a pipe122 into a cylinder chamber 123, the piston 116 will be moved downwardly(Fig. 7) to cause a downward movement of the piston rod 117 so as torock the platen 45 in a counter-clockwise direction about the axis ofthe tubular rod 36. During this movement fluid within a cylinder chamber124 may exhaust through a pipe 125. Similarly if fluid under pressure isreversed and fluid under pressure is passed through the pipe 125, thepiston 116 will be moved upwardly to cause an upward movement of thepiston rod 117 thereby swinging the platen 45 together with column 50and the swing frame grinder 56 in a clockwise direction. This mechanismjust described serves to impart a longitudinal reciprocatory stroke tothe grinding Wheel 58 relative to the work piece 70 being ground.

A fluid pressure system is provided for supplying flLlld under pressureto the various actuating mechanisms of the machine. In order to providea self-contained-unit, a fluid reservoir is provided within thevertically arranged column 50. A fluid pump 131 driven by an electricmotor 132 is mounted on the under side of a plate 133 which is fastenedto the right hand ends of the tubular rods 35 and 36 (Figs. 1 and 2).The pump 131 draws fluid from the reservoir 130 through a pipe 134 andforces fluid under pressure through a pipe 135 to the various mechanismsof the machine. A variable pressure relief valve 136 is connected to thepipe line 135 to facilitate returning excess fluid under pressurethrough the reservoir 130. The fluid pressure pipe 135 conveys fluidunder pressure through a pipe 135a to a plurality of control valves 137,138, 139 and 140 which are arranged to control the passage of the fluidunder pressure to and the exhaust of fluid from the fluid motor 23, thecylinder 75, the cylinder 90 and the cylinder 105, respectively. Thecontrol valves 137, 138, 139 and 140 are manually actuated valvescontrolled by operating handles 141, 142, 143 and 144 respectively. Thevalves 137, 138, 139 and 140 are identical in construction consequentlyonly one of these valves has been illustrated in detail in Fig. 6. Thisvalve will be hereinafter described.

Fluid under pressure from the pipe 135 also passes to a solenoidactuated control valve 145 for controlling the admission to and exhaustof fluid from the cylinder 115 so as to obtain an automaticallycontrolled oscillating or reciprocatory movement of the grinding wheel58. The solenoid valve 145 is a piston type valve having a slidablymounted valve member 146 having a plurality of valve pistons 147, 148,149 and 150 formed integrally therewith. The Valve member 146 isnormally held in a central position by a pair of balanced compressionsprings 151 and 152. A pair of solenoids S2 and S1 are provided to shiftthe valve member 146 in either direction. As positioned in Fig. 7 fluidunder pressure from the pipe 135 passes into a valve chamber 155 formedbetween the valve pistons 148 and 149 respectively. When the solenoid S2is energized, the valve member 146 moves toward the right so that fluidunder pressure from the pipe 135 passes through a valve chamber 155formed between the valve pistons 148 and 149 and passes out through thepipe 122 into the cylinder chamber 123 to cause a downward movement ofthe piston 116 so as to rock the plate 15 in a counter-clockwisedirection, thereby imparting a swinging movement of the grinding wheel58 also in a counter-clockwise direction. During this movement fluidwithin the cylinder chamber 124 may exhaust through the pipe 125 into avalve chamber 156 formed between them and passes out through a pipe 157,through a throttle valve 158 and through an exhaust pipe 159 into thereservoir 130.

Similarly when the solenoid S1 is energized, the valve member 146 movestowards the left (Fig. 7) so that fluid under pressure from the pipe 135entering the valve chamber 155 may pass through the pipe 125 into thecylinder chamber 124 to cause an upward movement of the piston 116thereby rocking the platen 45 together with the grinding wheel 58 in aclockwise direction.

' During this movement fluid within the cylinder chamber 123 exhauststhrough the pipe 122 into a valve chamber 160 formed between the valvepistons 149 and 150 and passes through a central passage 161 within thevalve member 146 into the valve chamber 156 and out through the pipe157, through the throttle valve 158 and the exhaust pipe 159 into thereservoir 130. It will be readily apparent that the throttle valve 158controls the rate of exhaust of fluid from either end of the cylinder115 and thereby controls the rate of movement of the piston 116 andthereby controls the rate of oscillation or reciprocation of thegrinding wheel 58.

It is desirable that the reciprocating movement of the grinding wheelcontinue automatically through a predetermined stroke. The platen 45 isprovided with an actuating arm 165 which is arranged to engage eitherthe actuating roller 166 of the limit switch LS1 or the actuating roller167 of the limit switch LS2.

An electric circuit is provided to supply electric current. A manuallyoperable starter switch 170 and a stop switch 171 is provided to stopand start the lateral oscillation or reciprocating movement of thegrinding wheel 58. The limit switch LS1 is a normally closed limitswitch and the limit switch LS2 is normally opened. The limit switchesLS1 and LS2 are connected through a relay switch 174 with the solenoidsS1 and S2 of the control valve 145. When the start switch 170 is closedcurrent passes through the contactor 172 of the relay switch 17 4 toenergize the solenoid S2 so as to shift the valve member 146 toward theright so that fluid under pressure passes into the cylinder chamber 123to cause a counterclockwise swinging movement of the platen 45 and thegrinding wheel 58. This counter-clockwise movement of the grinding wheel58 continues until the arm 165 engages the actuating roller 167 of thelimit switch LS2 which serves to make a circuit thereby energizing therelay switch 174 to open the contactor 172 and to close the contactor173. Opening the contactor 172 serves to deenergize the solenoid S2allowing the valve member 146 to return to a central position. Closingthe contactors 173 serves to allow current to pass through the relayswitch 174 so as to energize the solenoid S1 thereby shifting the valvemember 146 toward the left so as to admit fluid under pressure to thecylinder chamber 124 to start a swinging movement of the platen 45 andthe grinding wheel 58 in a clockwise direction. It will be readilyapparent from the foregoing disclosure that a continuous oscillation orreciprocation of the grinding Wheel is obtained. When it is desired tostop the oscillation of the grinding wheel, the stop switch 174 isopened manually to render the circuit inoperative thereby stopping theoscillation of the platen 45 and the grinding wheel 58.

A start switch 175 and a stop switch 176 are provided for stopping andstarting the motor 132 for driving the fluid pump 131. A start switch177 and a stop switch 178 are provided for controlling the stopping andstarting of the wheel driving motor 62.

The control valves 137, 138, 139 and 140 are identical in construction.These valves are arranged side by side and fastened together by aplurality of tie rods 180, 181, 182 and 183. The valve assembly isfixedly mounted on a vertical plate 184 supported at the operatorsstation 42.

Fluid under pressure from the pipe 135a passes through a longitudinalpassage 185 which extends through all four of the valves. Similarly anexhaust passage 186 extends through all of the valves 137, 138, 139 and140 and is connected to an exhaust pipe 187 to return exhausting fluidto the fluid reservoir 130.

As above stated the valves 137, 138, 139 and 140 are identical inconstruction consequently only the valve 140 has been illustrated andwill be described in detail. These valves are piston type valvescomprising valve stems 190 having valve pistons 191, 192 and 193 formedintegrally therewith. A compression spring 194 is provided, nor mally tohold the valve in a central or neutral position as indicated in Fig. 6.The control lever 144 is pivotally supported by a stud 195 on a link 196which is in turn pivotally supported by a stud 197 formed in an upwardlyextending lug 198 on the valve 140. The control lever 144 is connectedby a stud 199 with the upper end of the valve stem 190.

When the control lever 144 is moved toward the operator, that is, towardthe right (Fig. 6), the valve stem 190 is depressed so that fluid underpressure from the passage 185 enters a valve chamber 200 formed betweenthe valve pistons 192 and 193 and passes out through a passage 201,through the pipe 111 into the cylinder chamber 112 to cause a downwardmovement of the piston 106 thereby rocking the swing frame grinder unit56 in a clockwise direction about its longitudinal axis. During thismovement fluid Within the cylinder chamber 113 is exhausted through thepipe 114 into a valve chamber 202 formed by the valve pistons 191 and192 and through a passage 203, through the longitudinal passage 186 andthrough the exhaust pipe 187 into the reservoir 130.

Similarly as the control lever 144 is moved away from the operator, thatis, toward the left (Fig. 6) an upward movement is imparted to the valvestem 190 so that fluid under pressure entering the valve chamber 200passes through the pipe 114 to rock the swing frame grinder unit 56 in acounter-clockwise direction about its longitudinal axis. This valve asabove stated serves to position the grinding wheel 58 for grindingadjacent to either one corner or the other corner thereof. It will bereadily apparent from the foregoing disclosure that the valve stem 190is maintained in an upper or lower position only so long as the operatorholds it in either of these positions by means of the manually operablehandle 144. Upon release of the handle 144, the released compression ofthe spring 194 returns the valve stem 190 into the central or neutralposition as indicated in Fig. 6.

When the control lever 143 is moved toward the operator the valve 139 isshifted so that fluid under pressure passes through the pipe to cause adownward movement of the piston 91 to rock the swing frame grinder unitin a counterclockwise direction about the axis of the stud 53. When thecontrol lever 143 is moved away from the operator, fluid under pressureis passed through the pipe 103 to cause an upward movement of the piston91 so as to rock the swing frame grinder unit 56 in a clockwisedirection about the axis of the pivot stud 53.

Similarly when the control lever 142 is moved toward the operator fluidunder pressure is passed through the pipe 82 to cause a movement of thepiston 76 toward the right (Fig. 7) to cause a swinging movement of thecolumn 50 about the axis of the rock shaft 49 in a counter-clockwisedirection. When the control lever 142 is moved away from the operatorfluid under pressure is passed through the pipe 85 to cause a swingingmovement of the column 50 in a clockwise direction about the axis of therock shaft 49.

When the control lever 141 is moved toward the operator fluid pressureis passed through a pipe 210 to the fluid motor 23 to cause the carriage12 to traverse in one direction. During this movement fluid exhaustsfrom the other side of the fluid motor 23 through a pipe 211. Similarlywhen the control lever 141 is moved away from the operator fluid underpressure is passed through the pipe 211 to the fluid motor 23 to rotatethe drive shaft thereof in the reverse direction thereby imparting a longitudinal traverse movement of the carriage 12 in the reverse direction.

The operation of the improved snagging grinder will be readily apparentfrom the foregoing disclosure the controls for the machine are arrangedso that the operation thereof may assimilate the operation now obtainedmanually through manually operated swing frame grinding machines. A workpiece such as a billet 70 is positioned on the work support 71. The pushbutton 175 is actuated to start the fluid pump motor 132. The switch 177is actuated to start the wheel driving motor 62 to rotate the grindingwheel 58.

In a snagging operation of this type it is sometimes desirable to usethe peripheral face of the wheel and other times it may be desirable toutilize a corner portion at either side of the peripheral face toperform the grinding operation. A control lever 144 is provided tocontrol the admission of fluid under pressure to the cylinder so as torock the swing frame grinder unit 56 about its longitudinal axis so thatthe grinding wheel may be positioned so that the entire peripheral facemay be used or either corner portion thereof, as desired.

The control lever 141 is then manipulated to traverse the carriage 12longitudinally in either direction to position the grinding wheel 58 inposition adjacent to the portion of the billet surface to be ground. Thepush button 170 is then actuated to start an oscillating orreciprocating movement of the grinding wheel through a relatively shortstroke, such as for example, 3 feet.

The control lever 142 is manipulated to cause a swinging movement of thecolumn 50 to facilitate a transverse movement of the grinding wheel toposition it relative to the surface to be ground.

The control lever 143 is then manipulated to pass fluid under pressureto the cylinder chamber 101 to cause the swing frame grinder unit 56 toswing about the axis of the rock shaft 53 yieldingly to maintain thegrinding wheel 58 in operative engagement with the surface of the workpiece 70 as the grinding wheel 58 oscillates or reciprocateslongitudinally. While cylinder and piston 116 cause an oscillation 'ofthe platen 45, the column 50, the swing frame grinder unit 56, due tothe yielding action of the piston 91, the grinding wheel 58 will becaused to reciprocate longitudinally in a substantially rectilinear pathinstead of an arcuate path. After a portion of the work has been ground,the control lever 142 is actuated to cause a swinging movement of thecolumn 50 to position the grinding wheel transversely for grinding otherportions on the surface of the work piece 70. After the portion of thework piece 70 has been ground to the desired extent, the control lever141 may be actuated to traverse carriage 12 longitudinally to bring thegrinding wheel 58 in operative relation with a different-portion of theWork piece to be ground. By providing a relatively short reciprocatorystroke, the operator riding on the control station 42 may visiblyobserve the action of the grinding wheel 58 so that if more or lessgrinding is desired to remove seams or cracks from the billet this maybe done in the localities desired.

If desired, a plurality of spaced Work pieces, such as billets may beground. The first work piece is ground to the. desired extent, afterwhich the carriage 12 may be traversed longitudinally to position thegrinding wheel 58 into operative relationship with the next work pieceto be ground and the grinding operation may then be repeated, as abovedescribed, on the next workpiece.

It will thus be seen that there has been provided by this inventionapparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved.v Asmany possible embodiments may be made of the above invention and as manychanges might be made in the embodiments above set forth, it is to beunderstood that all matter hereinbefore set forth or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

I claim:

1. A snagging grinder having a pair of spaced parallel guideways, alongitudinally movable carriage thereon, a platen pivotally mounted onsaid carriage arranged to swing about an axis normal to said ways, avertically arranged column pivotally supported on said platen, a swingframe pivotally supported 'on the lower end of the said column, a motordriven grinding wheel on said frame, means including a fluid motor onsaid carriage operatively connected to traverse said carriagelongitudinally in either direction to facilitate positioning thegrinding wheel relative to the work piece being ground, and a fluidmotor operatively connected between the carriage and platen tofacilitate rocking said platen and column so as to impart areciprocating movement to said grinding wheel.'

2. A snagging grinder having a pair of spaced parallel guideways, alongitudinally movable carriage, a vertically arranged depending columnpivotally mounted thereon, said column being arranged to swing about anaxis parallel to and an axis parallel to said ways, a swing framepivotally mounted at the lower end of said column, a motor drivengrinding wheel on said frame, means including a fluid motor on saidcarriage operatively connected to traverse the carriage longitudinallyin either direction, means including a fluid motor operatively connectedto swing said column about an axis parallel to said ways so as to imparta transverse movement to said swing frame, means including a fluid motoroperatively connected to swing said swing frame relative to said columnso as to maintain the grinding wheel in operative engagement with thework piece being ground at the desired pressure, and means including afluid motor operatively connected to oscillate said column and swingframe about an axis normal to said ways in a direction parallel to thelongitudinal movement of said carriage so as to impart a longitudinalreciprocatory movement to the grindling wheel in a direction parallel tothe guideways.

3. A snagging grinder having a pair of spaced parallel guideways, alongitudinally movable carriage thereon, a platen pivotally mounted onthe carriage arranged to swing about an axis normal to said ways, avertically arranged column pivotally supported on said platen, saidcolumn being arranged to swing about an axis parallel to said ways, aswing frame pivotally supported at the lower end of said column, saidframe being arranged to swing about an axis parallel to said ways, amotor driven grinding wheel on said frame, means including a fluid motoron said carriage to traverse said carriage longitudinaly in eitherdirection to facilitate positioning the grinding wheel relative to thework piece to be ground, and an independent fluid motor operativelyconnected between the carriage and the platen to facilitate rocking saidplaten and the column so as to impart a longitudinal reciprocatorymovement to said grinding wheel relative to the work piece to be ground.

4. Avsnagging grinder having a pair of spaced parallel guideways, alongitudinally movable carriage thereon, means including a fluid motoron said carriage operatively connected to traverse said carriagelongitudinally in either direction, a platen pivotally mounted on saidcarriage arranged to swing about an axis normal to said guideways, avertically arranged depending column pivotally supported on theunderside of the said platen and arranged to swing about an axisparallel to said guideways, means including a fluid motor operativelyconnected between said platen and column to facilitate swinging saidcolumn transversely, a bracket pivotally supported on the lower end ofsaid column and arranged to swing about an axis parallel to saidguideways, a swing frame rotatably supported on said bracket, said framebeing arranged to be rotatably adjusted about its longitudinal axis, amotor driven grinding wheel on said frame, a fluid motor operativelyconnected to rotate said frame about its longitudinal axis to facilitatepositioning the operative face of the grinding wheel, and meansincluding a fluid motor operatively connected between the carriage andplaten to impart an oscillating movement to said platen so as to cause areciprocating movement of the grinding wheel relative to the work beingground.

References Cited in the file of this patent UNITED STATES PATENTS1,256,072 Stevenson Feb. 12, 1918 1,488,711 Rohlfing Apr. 1, 19242,308,842 Wilson Jan. 19, 1943 2,627,704 Whitehouse Feb. 10, 1953FOREIGN PATENTS 612,690 France Aug. 4, 1926 719,575 France Nov. 23, 1931

